Types of fire detectors, installation of sensors behind false ceilings. Installation of fire detectors behind a suspended ceiling Ceiling height for fire detectors

The design of the suspended ceiling allows you to hide exhaust ducts, wiring, electrical cables and other communications in the interceiling space, however, this increases the risk of fire. In this connection, the ceiling must be equipped with an automatic fire alarm system.

When sensor installation is necessary

As safety standards are constantly changing, homeowners with suspended ceilings need to regularly monitor new regulations. So, some owners are sure that it is the level of the ceiling height that is the fundamental factor in the need to install an alarm. However, this belief is incorrect - the requirements for fire protection do not depend on the height. ceiling space, but solely on the presence and amount of combustible cable load. This is legally regulated by the following regulations:

set of rules 13130 of 2009 with the obligatory appendix "A";
Table "A2", clause 11 and a note to clause 11 (“Fire protection” standard).

How to determine the need for installation:

Step 1... Look behind the ceiling, locate the power cable, outlet wires, or mains.

Step 2... Choose the largest possible section, drawn in one direction for more than a meter. Count the number of cables, taking into account their brands, write down the data.

Step 3... For each type of wire, determine the indicators of the combustible mass according to any directory of cable manufacturers, for example, the Kolchuginsky plant.

Step 4... Carry out calculations using the formula: A × B = C, where A is the number of wiring of a certain model and brand, B is the combustible mass, and C is the desired flammability parameter. The calculation is performed separately for each type of cable, then all the results are summed up.

Step 5... Compare the resulting figure with the legal regulations:

up to 1.5 liters per meter - there is no need to install sensors on the ceiling;
from 1.5 to 1.7 liters - fire safety is provided in the form of an independent ceiling-mounted alarm loop;
1.7 l and more - must be installed automatic system fire extinguishing. With a ceiling height of less than 0.4 meters, a loop is mounted.

In this case, the distance between the base floor and the false ceiling must be sufficient to accommodate the sensors. It is also important to identify the area with the most dense arrangement of wires and other communications - the cables should be at a distance of at least 30 cm from each other.

When a fire alarm is not required

The need to install an alarm is always determined solely by the indicator of the combustible load. However, a number of other factors are established in the safety regulatory documentation in which the installation of a fire alarm on a suspended or stretch ceiling is not required:

In the presence of wires hidden in insulated corrugated tubes or special steel boxes.
In the case of laying on the basis of a single-core cable and electrical supply NG type (non-combustion).
If there is a single conductor in the suspended ceiling.

Types of fire detectors

The existing sensors have a rather extensive classification system in accordance with the nuances of the structure of the apparatus and the methods of its functioning. Each of the detectors has its own installation and operation features. So, depending on the type of transmitted signal, sensors are divided into the following categories:

Single-mode detectors. They signal a danger when exposed to an external factor, such as temperature. Currently not used in everyday life.
Dual-mode with "Fire" and "No fire" sirens. At the same time, the absence of a fire signal confirms that the device is in good working order and is working in a regular manner.
Multi-mode with built-in programs for notification of device failures.

In addition, the detectors are conventionally divided into types according to their localization:

Point Appliances have a single sensor, often built into the housing.
Multipoint devices are equipped with multiple detectors.
Linear sounders analyze the space along an arbitrary trajectory. They can be single or paired, autonomous or targeted.

Regardless of the classification, all fire detectors are divided into wired and wireless and differ in the type of the detector itself - this is the division that is fundamental when choosing a notification system.

Heat detectors

Heat sensors were the first devices to prevent fires. They appeared in everyday life back in early XIX century, and at that time looked like two spring-loaded cables with a wax insert in the middle. As the temperature rises, the wax began to melt and the wires shorted, triggering an audible alarm. New generation heat sensors also have melting elements and often employ an electrical effect based on the thermocouple principle.

Despite all the advantages of the device, including its cheapness, such detectors have one serious flaw - they give an alarm signal after the air temperature has risen and a fire has started. For this reason, with the development of technology, this type of device has gradually lost its relevance.

Smoke detectors

Systems equipped with smoke detectors, are by far the most popular fire protection devices for use in residential and work areas. Smoke is the first and main feature possible fire that may occur before open flame... For example, a wiring malfunction is often accompanied by a long process of smoldering with a characteristic pungent fume. Therefore, this type of sensors helps to identify the source of fire at its initial stage.

The smoke detector operates on the basis of the principle of detecting a change in the transparency of the smoke air. In this case, the device is classified, depending on the methods of its operation, into linear detectors (work with a directed beam in the optical or ultraviolet range) or point detectors (based on infrared radiation). Point detectors are usually simpler than linear detectors, but less reliable - thick dark smoke does not have the property of reflecting infrared rays, therefore, during such a fire, the detector may not react.

Flame detectors

This type of sirens is usually used to provide countermeasures fire safety at production sites. In such rooms, the use of smoke or heat detectors will be difficult due to the constant dustiness of the air or its elevated temperature.

Types of detectors:

Infrared. Captures the radiant heat of an open flame. In the presence of regularly operating sources of air heating, an unreasonable signal triggering is excluded.
Ultraviolet. They are used if there are sources of infrared radiation in the room, for example, an electric heater.
Sensors with a reaction to the electromagnetic component of the energy release of an open fire.
Security ultrasonic devices. Interact with fluctuations in air masses. The principle of operation is based on the fact that hot air actively rises up.

Rules for installing and placing fire detectors on the ceiling

Accommodation burglar-fire alarm(OPS or APS) is regulated by the normative act SP 5.13130.2009 as amended on 01.06.2011. In accordance with this document, the installation of devices is carried out exclusively on load-bearing elements (stiffeners) or cables. It is important to take into account that it is strictly forbidden to fix the sirens on the slabs of the suspended ceilings - this design has poor mechanical stability and low fire resistance.

Sometimes sensors in the ceiling space are also used to provide security in the room. This is possible in cases where the false ceilings have large perforations. According to safety rules, installation of fire detectors behind a suspended ceiling is possible in the following cases:

in the presence of perforation with an area of 40% of the entire surface with a periodically repeating large pattern;
with a diameter of one perforation hole of at least 1 cm;
in case item size suspended structure does not exceed the minimum size of one cell (for example, Armstrong ceilings).

If these requirements are not met, fire detectors must be installed on the walls of the room or directly on the surface of the suspended ceiling. In addition, the sensitivity radius of the instruments must be taken into account.

Installation is carried out according to the "triangular grid" arrangement - this will save space and protect the entire surface.
When calculating the range of the device, the orientation of the sensitivity zone in the horizontal plane is used. For smoke detectors - 7.5 m, for heat detectors - 5.3 m.
A detector mounted on the base of a suspended structure must be positioned so that the sensing element is below the ceiling level. For smoke - by 2.5-60 cm, heat - by 2.5-15 cm.
The distance from the walls must be at least 0.5 m.

Calculation of the required number of detectors

Before installing smoke sensors, it is necessary to correctly calculate their exact number for a particular room. In this case, it is necessary to take into account the type of devices and the intended connection diagram. It is important to understand that in the legislation of each state, installation standards will differ.

V Russian Federation installation of at least 2 sensors per room is required. The regulations state that it is recommended to install detectors on each section of the ceiling with a width of 0.75 m or more, as well as on elements building structures with a ledge of 0.4 m.

Thus, a separate area of the interceiling space should be equipped with:

three sensors, if they are connected to a two-threshold reaction loop or to three separate loops with a single response threshold;
four detectors when they are connected in pairs in two different loops of devices with one threshold;
two devices with alternating operation circuit.

Despite the fact that point sensors are able to control up to 25 meters of a room, it is imperative to install at least two pieces if they are addressable and at least three if analog. This is explained by the fact that the spread of smoke and fire in the ceiling zone has its own characteristics, which means that this area is more difficult to control.

Installation procedure

At the beginning of the installation of the device, first of all, it is determined required amount sensors and attachment points, only then the installation process begins.

In the false ceiling

In plasterboard suspended ceilings, sensors are most often installed using the insertion method - the most aesthetic and convenient way. In this case, it is recommended to use heat-resistant cables with an NG braid, copper conductors and a minimum cross-section of 0.5 mm. It should be noted that the installation of sensors in blind corners between the wall and the ceiling is strictly prohibited.

Fire sensor installation diagram:

Step 1... Determination of the number of detectors, their approximate location and distance from each other. It should be noted that smoke detectors must be installed both in the suspension structure itself and on it.

Step 2... Fixing the sirens is allowed only on the frame or concrete floor in an overhead way. Possibility of inserting into the false ceiling and fixing with the help of special mounting rings, but at the same time the sensor is additionally fixed with a cable to the ceiling.

Step 3... The device is connected exclusively when there is no power supply and in accordance with the diagram indicated on the sensor packaging. In conclusion, you should check the accuracy of the connection and the operability of the entire system several more times.

In a stretch ceiling

The regulatory documents do not indicate the mandatory location of fire detectors in stretch ceilings, however, it is necessary to observe minimum distance from the walls. When installing the device, preference should be given to those areas where there will be the greatest coverage of the room control, taking into account the range of the sensor.

Installation instructions:

Step 1... Prepare the embedded structure for stretch ceiling... To do this, flexible metal hangers are screwed to a flat plate made of plastic or plywood, with which the platform is attached to the concrete floor.

Step 2... Align the mortgage with the future ceiling. Lead the wiring down.

Step 3... Stretch the canvas. At the location of the platform, glue a thermal ring so that the PVC film does not break, then cut a hole for installing the sensor.

Step 4... Connect the device, check its functionality. Screw the sensor to the platform.

Safety measures and possible installation problems

Despite the fact that the system fire alarm must be installed by a qualified organization in compliance with all requirements and norms, sometimes the apartment owners try to mount the device with their own hands. Self-installation fire detectors is possible, but must be observed certain rules security:

During installation works it is allowed to use only special stepladders or ladders - any means at hand are strictly prohibited.
For installation and maintenance fire safety systems, specialists with knowledge of the instructions and the specifics of work are allowed.
Tools used in the process must have insulated handles.
First, you need to measure the voltage between the phases using a portable voltmeter.
Before installing the system elements, it is imperative to check the firmness of fastening the fire detectors to the suspended ceiling or tension structure.

Common problems during installation and operation

Problem # 1: malfunction of one detector when all the others are working properly.

Remedy: check the installed smoke sensors and, if necessary, dismantle them. It should be borne in mind that if the voltage indicators are different, then the wiring for fire extinguishing and signaling should be located in separate boxes. With an open installation, the distance between cables and other communication systems should not be less than 0.5 m.

Problem # 2: no alarm.

Remedy: check mounting surface, unfold the optical indicator of the device towards the main entrance.

Problem number 3: battery failure.

Remedy: if the sensor is installed on the ceiling itself, then it will be quite easy to change the power system - you just need to carefully unscrew the device from its platform. When installing the device inside a false ceiling, it will be necessary to partially dismantle the ceiling sheet.

Thus, the main requirement for the installation of a fire detector remains its effective subsequent operation. When choosing a device, it is advisable to give preference to reliable manufacturers, whose models are guaranteed to last several years.

It is better for the owner of the premises to rely on qualified specialists who can calculate the number of detectors and create correct scheme their location - only with proper installation is it possible to operate fire detectors without failures and malfunctions.

Good afternoon, Dear Readers and Colleagues! The topic of our discussion today is fire protection behind the false ceiling. The question is as follows - as has been said more than once in our topics, fire safety standards are in constant active transformation and can undergo changes up to several times in one calendar year. Therefore, it is necessary to constantly keep abreast of current documents and the latest adopted amendments to these relevant documents. This article is written more for the category of Readers - Building Owners, than for normative or experienced designers. The fact is that many of the owners of premises are still confident that it is the height of the ceiling space that is the dictating factor for determining the need to install fire detectors there (behind the ceiling). That is, if it is more than 40 centimeters, then it is necessary to install detectors, and if it is less than 40 centimeters, then fire protection behind the suspended ceiling is not needed. Even during the construction (finishing) of the premises, the owners set conditions for the builders to minimize the height of the ceiling space based on the critical distance - 40 centimeters. This is not true. Today, fire protection behind a false ceiling does not depend on the height of the ceiling space! Fire protection behind a suspended ceiling (and not only its presence, but the type of protection itself) depends solely on the presence and amount of combustible cable and other loads in the ceiling space.

First, let's give regulatory framework- SP5.13130.2009, Appendix "A" (mandatory), table "A2", clause 11, and also see the note to clause 11 under the plate - standard " .

11 Spaces behind false ceilings and under double floors

when laying air ducts in them, pipelines with insulation, you

filled with materials of the flammability group G1-G4, as well as cable

lei (wires), flame retardant (NG) and having a code

fire hazard PRGP1 (by), including with their joint

gasket (2) :

11.1 Air ducts, pipelines or cables (wires) with volume

combustible mass of cables (wires) 7 or more liters per meter cable-

noah line (CL), including when laying them together - equipped with APT installations, n regardless of area and volume;

11.2 Cables (wires) of the NG type with a total volume of combustible mass from

1.5 to 7 liters per meter of cable line - equipped with APS installations, regardless of area and volume.

Note (2):

1 Cable structures, spaces behind false ceilings and under double floors with automatic are not equipped with new devices (except for items 1-3):

a) when laying cables (wires) in steel water and gas pipes or steel solid boxes with open removable solid lids;

b) when laying pipelines and air ducts with non-combustible insulation;

c) when laying single cables (wires) of the NG type for powering lighting circuits;

d) when laying cables (wires) of the NG type with a total volume of combustible mass less than 1.5 liters per 1 meter of cable lines behind the suspended ceilings made of materials of the flammability group NG and G1.

2 If the building (room) as a whole is subject to the protection of the AUPT, the space behind the suspended ceilings and under double floors when laying air ducts in them, pipelines with insulation made of materials of the group ryuchestvo G1-G4, or cables (wires) with a volume of combustible mass of cables (wires) more than 7 liters per 1 meter of cable line is necessary protect with appropriate installations. Moreover, if the height from the ceiling to the false ceiling or from the black level floor up to the level of the double floor does not exceed 0.4 m, the AUPT device is not required.

3 The volume of combustible mass of cable (wire) insulation is determined according to the methodology of GOST R IEC 60332-3-22.

Now let's decipher all this clearly and understandable language... We look behind the suspended ceiling, we see a cable for powering lighting networks (ceiling lamps), it is also possible some kind of cable for outlet groups, there may be a power cable to floor lighting panels or other electrical panels, there may be a communication cable or computer cables or control cables for which or engineering systems or some kind of wires for burglar alarm... We choose a section of the cable route, where all this cable products are collected as much as possible, laid in one direction for at least one meter, we count the number and brands of cables and wires and carefully write down the data in a notebook. Next, we turn to the directories of cable manufacturers (I recommend the directory of the Kolchuginsky plant, which can be found very simply on their website) and opposite each of the cable brands laid behind the suspended ceiling and written in a notebook, we write down the indicator of combustible mass per 1 running meter of the corresponding cable or wire taken from the specified directory. I will give some of the data I have on the combustible weight of cable products per meter - download here and use in the calculations. Further - just arithmetic, i.e. for example a bunch of 10 pieces VVGng-LS cable VVGng-LS TU 16.K71-310-2001 round conductors 0.66 kV2x1.5 with combustible mass 0,044 liters per 1 running meter will be 10 x 0.044 = 0.44 l / 1 meter CL. That's all - it's simple. Further, in a similar way, we consider the communication cable, then the computer cable, and so on. Further, we add all the data obtained - for example, from power circuits - 0.44, plus from computer circuits - 0.55, plus from a communication cable - 0.70, plus from control cables - 0.55. Everything means - 0,44+0,55+0,7+0,55 = 2,24 liters / 1 running meter CL. This figure 2,24 and there is the required parameter of the combustible load.

Now we turn to the text of the above-described regulation “fire protection behind a suspended ceiling”:

If an NG cable is laid behind the ceiling and the combustible load is up to 1.5 liters per 1 meter of cable line, then the detectors do not need to be installed behind the suspended ceiling, that is, they are not needed;

If an NG cable is laid behind the ceiling and the combustible load is in the range from 1.5 to 7 liters per 1 meter of cable line, then it is necessary to protect the substation in the ceiling space, i.e. necessary in the form of an independent ceiling-mounted fire alarm loop;

If a cable of “NG” or not “NG” brands is laid behind the ceiling (it makes no difference here already) and the combustible load is more than 7 liters per 1 meter of cable line, then the space behind the suspended ceiling needs a PT, that is, fire protection behind the suspended ceiling in the form of a fire extinguishing system. An exception is the ceiling space with a height of less than 0.4 meters - there is no APT (see carefully the application of the norms - set out above), but there is simply mounted an APS loop, as if the combustible load would be within the range of 1.5 to 7 liters per 1 running meter KL.

If a non-NG cable is laid behind the ceiling, and you do not want to install fire extinguishing, then you must either replace this cable with NG, or place this cable in metal pipes or metal blind boxes. In this case, the installation of ceiling-mounted fire detectors does not compensate in any way for the violation in the form of using a non-“NG” cable over the ceiling that is not laid in pipes or ducts. Only fire extinguishing can compensate for such a violation.

Well, in fact, all the calculations - everything is extremely simple and does not raise questions. If you still have questions or clarifications or objections, then write in the comments - we will consider and continue the dialogue. If everything is clear and good - put "like" - to support our desire to continue to write similar articles. I authorize to copy my article "fire protection behind a suspended ceiling" for publication on other resources, provided that all the links to our site are preserved in the text... As usual, I invite you to read our other articles on the links:

- how many fire detectors should be installed in a compartment bounded by beams of more than 0.4 meters?

- cable penetrations "Stop-fire"

- fire detector on the wall

- smoke exhaust systems, compensation

- initial data for design

- shutdown of ventilation in case of fire

- wall-mounted sounders in rooms with a height of less than 2.45 meters

- fire detectors in the ceiling compartment with beams over 0.4 meters (clarification)!

- fire safety requirements for underground parking

- new regulatory documents

- fines for violations in the field of fire safety

- calculation of sound pressure at the facility

Technical report - what is it for?

Addressable fire detector - how much per room?

I wish everyone a constant increase in the level of knowledge normative documents and success in your work!

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: 17 comments

And what if, in addition to cables, water supply pipes are laid under the ceiling - polypropylene material in K-flex insulation, sewage pipes made of polypropylene?
Where to get this data to calculate the combustible load
For me, the following is missing in the article: the volume of the combustible load is considered only for "NG" cables, and values up to 1.5; from 1.5 to 7, and more than 7 liters per meter of cable line will be valid only if cable lines ceiling space using NG cables. The presence of at least one non-NG cable or wire (TRP, KPSVV, etc.) no longer gives the right to an exception, even if the volume of the combustible load is less than 1.5 liters. Please do AUPS. or hide such cables in a met pipe, etc.
1. Post author
  Hello! You are a little wrong. You write “it is considered only for“ NG ”cables, and values up to 1.5; from 1.5 to 7, and more than 7 liters per meter K ”.
  Let's read the paragraph again literally:
  11.1 Air ducts, pipelines or cables (wires) with volume
  combustible mass of cables (wires) 7 or more liters per meter cable-
  line (CL), including when they are jointly laid, are equipped with APT installations, regardless of the area and volume; ……. AS YOU SEE, IF THE WIRES AND CABLES ARE NOT “NG” AND THE VOLUME EXCEEDS 7 LITERS, THEN YOU SHOULD DO FIRE EXTINGUISHING, and not only for NG, as you write above ..
  Items in the note up to 1.5 liters and from 1.5 to 7 liters are really considered only with the use of cable type "NG".
  11.2 Cables (wires) of the NG type with a total volume of combustible mass from
  1.5 to 7 liters per meter of cable line - regardless of the AUPS area. and in the note point NOT EQUIPPED d) when laying cables (wires) of the NG type with a total volume of combustible mass less than 1.5 liters per 1 meter of cable lines behind the suspended
  ceilings made of materials of the flammability group NG and G1.
  THE CONCLUSION IS THIS:
  - IF THERE IS A CABLE NOT "NG" AND THE FLAMMABLE LOAD EXCEEDS 7 LITERS, THEN IT SHOULD DO THE FIRE EXTINGUISHING.
  - IF THERE IS A CABLE NOT "NG" AND THE COMBUSTION LOAD IS LESS THAN 7 LITERS AND LESS THAN 1.5 LITERS PER METER OF CABLE LINE, THEN THIS OPTION IS NOT PROVIDED BY THE REGULATIONS IN THE PART OF THE MANUAL, AND THIS IS NOT ANYTHING TO DO DOESN'T MEAN WHAT IS NECESSARY TO DO AUPS AND EVERYTHING - WHAT IS A JOY?
  - IF THE CABLE is “NG”, THEN A SIGNALING IS PROVIDED (AT A FLAMMABLE LOAD FROM 1.5 TO 7 LITERS) AND NOTHING IS NECESSARY TO DO WHEN A LOAD UP TO 1.5 LITERS.
  Your proposal “Please, do AUPS. or hide such cables in a met pipe, etc. " is not substantiated by anything. WHY ASKED AUPS TO DO AND NOT AUPT? BECAUSE YOU LIKE IT SO ??? This is not true, you just need to either change the cable to "NG" or lay the existing cable "NOT NG" in metal pipes or ducts in order to comply with paragraph "a" of the application ... ... ie.
  a) when laying cables (wires) in steel water and gas pipes or steel solid boxes with open
  removable solid lids; AS SEE HERE THERE ARE NO REQUIREMENTS for “ng”.

Quote grek on 01/25/2011 02:03:42 PM

Are my questions being deliberately ignored?

--End Quote ------- yes, your questions are not ignored, dear.
You simply cannot answer your questions unequivocally.
We all read the same text in Table A.2 of Appendix A to SP5, but we understand each one differently.
The Normator deliberately confused us with his delights of the Russian language that the MPH will figure it out.
For example:
- in footnote No. 1, the concept of a cable structure is given, which lists, among other things, double floors. But right there, in footnote No.-2, and cable structures and separate double floors. What for? Error? Or deliberately? Unclear. But this is just a saying.
- Clause 11 of Table A.2 tells us clearly and specifically about NG and PRGP1 cables. But right there, in subparagraph 11.1, cables are already any (regardless of NG and PRGP1), and in subparagraph 11.2 cables are indicated only with the letters NG, but without PRGP1. The same story with the exceptions indicated in paragraph 1 of footnote no.-2. When choosing a method of protection, is it necessary to take into account the execution of cables (simply NG or NG + PRGP or any)? Or should the footnote be considered to refer to the whole of clause 11? But this is only the second saying.
- if, to simplify understanding, we only talk about cables, then paragraph 2 in footnote No.-2 will look like this: "If the building (room) as a whole is subject to the protection of the AUPT, the space behind suspended ceilings and under double floors when laying in them ... cables with a combustible mass of cables of more than 7 liters per 1 meter of cable lines must be protected with appropriate installations. " Which relevant ...? Indeed, for these conditions (7 liters or more), subparagraph 11.1 has already been written, which unambiguously requires AUPT. Why write the same thing a second time?
- we remove this ridiculous repetition and then point 2 in footnote No. 2 will look like this: "If the building (room) as a whole is subject to AUPT protection, but the height from the ceiling to the suspended ceiling or from the level of the subfloor to the level of the double floor does not exceed 0.4 m, the AUPT device is not required even when laying cables with a combustible mass of cables in them more than 7 liters per 1 meter of cable line. Now it becomes clearer. But not quite. This AUPT can not be thrust into this narrow space, but just AUPS is necessary or not with these = less than 0.4 m =, but = more than 7 l =? It is not clear.
- It is not clear because clause 11.2 considers only a specific case for cables of the NG type with a total combustible mass from 1.5 to 7 liters per meter of cable line. Here, if you please, AUPS regardless of the area and volume, as for paragraph 11.1. But after all, for clause 11.1, an exception has been made in the case of a height of up to 0.4 m.

Among other things, in all this clause 11, when listing the elements and conditions, several different meanings are used = and =, = and also = and = or =. If the norm makers use these different phrases deliberately, then it turns out that, for example:
- in subparagraph 11.1, as well as in paragraph 2 of footnote No.-2, the condition for protecting the space is one of two things - OR laying pipelines ... OR laying cables ...
But in clause 11 itself, the turnover = and also = is used. It turns out that it is only necessary to protect spaces if both pipelines and cables are laid.

The absurdities and ambiguities can be continued, but ini will no longer be relevant to your question.
So, in order to answer your specific question, you need to know:
- the suspended ceiling itself is made of materials of which flammability group?
- execution of the cables used - without execution, simply NG or NG + PRGP. And if the PRGP, then which one?
- a way of laying cables (pipes, ducts (what?) or open?
- the purpose of the cables? Maybe you can use item c) of paragraph 1 of footnote No.-2?
- and, of course, = liters per meters = are definitely needed.

That is why no one wanted to contact you and unambiguously answer your question.
In short - FOR ALL OF THEY ARE HEALTHY !!!

During the construction of the building, fire safety is of paramount importance. The life of people depends on the installation of the necessary sensors. For this reason, alarm sensors are installed in the room. If there is a plasterboard structure on the ceiling, these devices can be installed on it. In this case, some questions arise: what are the requirements for fire safety? When is it necessary to install detectors and when not?

Fire system requirements

The fire safety documents indicate that sensors are defined by the value of the combustible mass of one meter of wiring. They are not installed in places where there is nothing to burn. But, if they are necessary, there are requirements for them:

During installation, keep the distance between the base ceiling and the suspended ceiling, it should be enough to accommodate wires and sensors.
Correctly count the number of appliances and combustible materials to ensure complete safety.
Examine carefully the ceiling surface to identify the area where the most dense arrangement of cables and other communications. The wiring should be 30 cm apart.
Determine the length of each cable brand separately. To do this correctly, refer to the special table with the data of combustible substances (measured in liters).
If the number is less than 1.5 liters, then there is no need to install detectors behind the false ceiling. Otherwise, it is necessary to install a loop, and therefore sensors.

Variety of sensors

These devices have differences and they can be divided according to some parameters. Sources of sensors triggering are heat, smoke and fire.

They differ in the nature of their detection.

Spot are smoke and heat detectors that control the situation only in the place where they are installed. Most often used.

Linear sensors are used less frequently and monitor the rise in temperature or smoke in parts of the linear space of the building.

They are connected to control devices by wired and wireless methods.

Addressable is an alarm system that identifies each detector individually.

Autonomous sensors are equipped with a sounder and a built-in battery. There is no need to connect it to the device, since its use in large buildings makes it difficult to verify the operation.

Point-to-point sensors have recently become known on the market. What are they? These are two devices located in the same housing, but located at a distance of 80 centimeters from each other. One sensor monitors the base ceiling and the other monitors the suspended ceiling. From separate loops, both sensors are connected to a 6-pin base. This option simplifies both the dismantling and installation of appliances that serve the space between the ceilings.

Smoke detector

Install such devices in those places where fire can be accompanied by big amount smoke. These are office premises, cinemas, clubs and trade enterprises.

Modern detectors are quite attractive in appearance, they do not spoil the interior. They are mounted using the cut-in method, which helps to use them on plasterboard ceilings.

The gross violation is the refusal to fix the wiring loops directly to the control devices.

Sensors can work falsely and sometimes fluorescent lamps contribute to this. This happens when the norms for the distance of sensors and lamps are not adhered to. The devices also react to the guidance of the ceiling fixing fittings. To avoid this, choose a quality product.

Infrared linear sensor

When a fire alarm is needed in large rooms, it is recommended to purchase exactly this type of sensors, and not a point one. The price is, of course, higher, but the equipment of the entire system will cost several times cheaper.

When sensor mounting is not required

The wires are hidden in corrugated pipes or special steel boxes.
Cables in insulated tubes.
The gasket was made with a single-core electrical supply wiring of the NG type.
An NG type wiring was used, but which does not contain more than 1.5 liters of combustible substances per meter.

Installing sensors

Where and how many devices to install is written in the recommendations. It is advised to install multipoint. When installing behind the suspended structure of the point sensor, keep a distance of at least 0.5 meters from the wall, and 0.1 - 0.3 meters from the ceiling. Do not install sensors in corners between ceilings and walls. The distance from the luminaires should be at least half a meter and they should be positioned so that there is free space around each device at a distance of 0.5 meters.

When mounting the wireless device in the absence of ventilation, place them behind a structure in a free space, only in the upper part.

Conventional detectors require separate loops for connection in the space between ceilings. Install above the main sensor, which is ceiling mounted. Provide the sensor itself with a powerful indicator light. Connecting the device provides control of the health and operation of the sensor and the electrical circuit.

Installation instructions

To begin with, the number, place, distance of devices is determined. Sometimes the sensors have to be mounted both in the suspended structure and behind it.

The sensors can only be fixed to load-bearing parts: on a frame or a concrete floor.

There are two types of sensor gaskets: mortise and invoice.

The second method is simpler, but does not look aesthetically pleasing. Use special rings or other tools to make a cut. Please note that the sensors are made of plastic or metal.

On plasterboard ceilings installation is more often used by the insert method, it has a beautiful appearance, and on plastic panels, only this method is used, because the material is too weak for overheads.

Sensor connection diagram

Fire safety regulations recommend using only flame retardant and insulated cables that are flame retardant. Their veins must be copper and with a cross section of at least 0.5 mm. The diagram is located on the package with the sensor and on the control unit. They are not complicated and are similar to each other. The main thing is to observe the order of work and correctly connect the contacts.

Connect the device only when the power is disconnected. After installing and connecting the circuit, it is better to check again how correct the connections and system performance are.

Placement of sensors

Four detectors are required if they are connected in pairs to different loops with the same threshold.

Two devices, if the connection was made according to a scheme that requires sequential operation of at least two devices and with a guarantee of replacement if necessary.

Two sensors, if they were connected to the circuit, when one device is triggered.

From this it follows that the norms are as follows: for ceiling structure v mandatory two sensors are mounted if they are addressable by type. The same amount is required if the devices are analog.

If they are analog, but the connection comes from two electrical circuits control devices that have one threshold.

It is allowed to install one addressable sensor in the room if the alarm system does not control the fire extinguishing and guarantees the absence of false alarms.

Security measures

If the supply voltage is different, then the wiring for the fire extinguishing and alarm system is mounted in separate boxes. If the gasket is performed open way, and there is no protection, then the distance between the wiring and harnesses with different voltages should be at least 0.5 m. Using single-core wires, the distance is halved.

In crowded places, fire safety is monitored more strictly. In places for entertainment or nightclubs and other institutions, there are special requirements to safety.

When installing plasterboard ceilings, you can face the same problems. The structure must comply with fire safety standards, besides, it must have an aesthetic appearance and be functional.

The cellular ceiling complies with these standards. It is made of aluminum. It is a material that does not burn and does not contribute to the spread of fire. The structure is open, like lattices with different sizes and drawings. Such properties help to install fire alarms behind the plasterboard structure, while not interfering with the functioning of the installed systems.

The cost of execution of suspended ceilings includes work on ventilation, installation engineering communications, installation of lamps and electrical wires.

The requirements that are put forward for a sensor located behind the ceiling are that it does not prevent it from working in the right time, and those in the room could leave it. For this reason, the material should not be flammable, degraded from high temperatures or exposure to fire. A properly installed ceiling fire alarm is effective. Mineral fiber does not ignite and slows down the process of fire, which allows for the evacuation of people. The standard thickness of mineral fiber boards is 1.5 centimeters. They protect the space between the ceilings and the entire room from fire from below and from above.

Since the action of these sensors, if installed at home, save lives, they are installed in apartments and houses. The alarm, which is located behind the false ceiling, warns of smoke or fire. For this reason, you can avoid unpleasant consequences that the fire brings. After all, fires often happen at a time when people are asleep and cannot manage to escape. This leads to the fact that the tenants receive severe intoxication with fumes or smoke, in other cases a fatal outcome is possible.

Fire detectors are divided into fire and smoke detectors. They have the same function - to warn of danger.

They differ only in that the smoke alarm is triggered when smoke or a heating source appears. Such sensors are used most often and their cost is affordable. Fire alarm can be triggered by a single sensor.

At home, it is enough to have one sensor that works on batteries. Some devices operate from a 120 volt network, and if the electricity is cut off, then they are powered by a battery. The batteries should be changed once a month.

Installation Requirements

These are the points that are applied so that subsequently there will be no problems and mistakes.

The sensor is connected in such a way that, after dismantling, it does not interfere with the work of others.
The surface on which it is installed must not be transferred without the use of a tool. In addition, the device itself should be turned so that the optical indicator looks towards the main entrance to the room.
The control panel is placed closer to the central entrance. If there is a round-the-clock duty at the facility, an indication and control panel is installed in the room where the security is located.
In the building where the main fire safety system is located, other local systems are connected to it in order to provide a signal: "Fault" or "Fire".

How to install detectors, see this video: